Fluorine-containing silicon network polymer, insulating coating thereof, and electronic devices therewith

ABSTRACT

A fluorosilicon network polymer prepared by the reaction of a tetraholosilane of the formula 1: SiX4 with an organohologen compound of the formula 2: RZ , an insulating coating prepared therefrom, semiconductor devices coated therewith, and processes for producing the same. In said formulas, R represents at least monofluorinated alkyl or aryl; and X and Z represent each independently boromine, iodine or chlorine.

TECHNICAL FIELD

The present invention relates to silicon network polymer containingfluorine in polymer structure, an insulating film and a manufacturingmethod thereof. Further, the present invention relates to a method offorming a thin film by a photolithography method, using silicon networkpolymer containing fluorine in polymer structure.

BACKGROUND ART

In the Journal of The Japanese Society of Applied Physics, Volume 34,L452, 1995, there is disclosed silicon network polymer and thesynthesizing method thereof. The synthesizing method uses Wurtz'sreaction in which trihalosilane is condensation-reacted with sodiummetal.

Further, in Japanese Patent Application Laid-Open No. 3-258834 (1991),there is disclosed straight chain fluorine-containing polysilane and thesynthesizing method thereof. This also uses Wultz's reaction.

However, in the prior art, fluorine-containing silicon network polymerhas never been synthesized. The reason is that the compounds which canbe used for the Wurtz's reaction are limited, and in particular there isno raw material for the fluorine-containing silicon network polymer.

In electronic devices, typically a semiconductor, it is extremelydesired to obtain an insulating layer with lower permittivity in orderto improve its performance. In order to respond the above-mentionedrequirement, there has been studied a plasma TEOS film by a CVD method,a SiOF film, etc. However, in order to form those films, it is necessaryto provide a CVD equipment, and further the productivity is low. Fromsuch a point of view, prior art uses a coating method to form theinsulating layer.

In the Journals of The Japanese Society of Applied Physics, Volume 77,2796 (1995) and Volume 34, L452 (1995), there are disclosed methods offorming a SiO film by using silicon network polymer. However, becausethe silicon network polymer containing no fluorine is used, it isimpossible to obtain the desired insulating layer with lowerpermittivity.

Further, because the stability of the straight chain fluorine-containingpolysilane is low, it is impossible to form the desired insulating layereven if the methods disclosed in the Journals of Japanese Society ofApplied Physics, Volume 77, 2796 (1995) and Volume 34, L452 (1995) areapplied.

While organic spin-on-glass (hereinafter, abbreviated as SOG), one ofpolysiloxane type coating material can provide the insulating layer withrelatively low permittivity, the stress is large when hardened. It isimpossible to form the desired insulating layer except the insulatinglayer with thickness of sub-micron order. Further, the workability islow and thus it is apt to crack.

As the semiconductor is highly integrated, the irradiation light of farshorter wave is required for use of photolithography in order to obtainfine wires. While in the photolithography g-line (436 nm), one of theemission characteristics of a mercury lamp was commonly used, recentlyi-line (365 nm) more suitable to fine working has become more used. Thefine working is carried out by using photo resist of which a majorcomponent is organic macromolecules containing aromatic ring within itsmolecules. In the development process of forming patterns, a wetdevelopment method due to solvent or a dry etching method due toreactive gas is used.

It seems that the microstructures of semiconductors will be furtherimproved. However, previously the photo resist of which a majorcomponent is organic material is not suitable for the lithography whichuses the light with wavelength shorter than 350 nm in which it has theself-absorption action against the wavelength shorter than 350 nm.

As main light sources of which the wavelength is equal to or less than350 nm, there are far-ultraviolet or excimer laser such as KrF (248 nm)or Ar (193 nm). The spotlight centers on the photolithography in whichthe combination of the light source with short wavelength and polysilaneof which sensitivity falls within the short wavelength area are used.However, a pattern forming method which uses these polysilane resistalso utilizes a wet development method or a dry etching method in whichreactive gas is used. (see SPIE, Vol.1466, P211 (1991))

Further, in order to form active elements such as transistors, diodes,etc. on the substrate of a semiconductor, it is necessary to performmore complicated processes such as oxidation reaction, impuritydiffusion, ion implantation, etc. in addition to the above-mentionedwiring forming process.

In addition, in order to form light wave-guiding passage, etc., it isnecessary to pass through furthermore complicated processes such asetching, coating, etc. Accordingly, there are many problems in theefficiency of manufacturing, the yields, etc.

DISCLOSURE OF INVENTION

An object of the present invention is to provide a newfluorine-containing silicone network polymer, an insulating film of thepolymer and a manufacturing method thereof.

Another object of the present invention is to provide an electronicdevice such as an integrated circuit which the insulating film of thepolymer is used, a semiconductor, etc. and a manufacturing methodthereof.

Large amounts of organic solvent are used in the wet etching for thepattern forming. Further, because the resolution at the edge of apattern is small, it is very difficult to form fine patterns. Inaddition, because it is necessary to use special-purpose and expensiveequipment in order to perform the dry etching, the throughput isdeteriorated.

Particularly with regard to the resist of which a major component ispolysilane, it is possible to perform the photo lithography by using theshort wave less than 350 nm. However, since large amounts of organicsolvent such as xylene or toluene are used in the wet-etching, and thesesolvents are flammable and extremely poisonous, it is very difficult toindustrialize.

Further, As to materials of a silicone system, typically SiO₂, it isrequired to use, for example, CVD equipment to form an SiO₂ film.Therefore, there is a problem in productivity. In order to solve theproblem, it can use paint type materials of a siloxane system calledspin-on-glass (hereinafter, abbreviated as SOG). However, because withregard to SOG, the stress when hardened is large, it is impossible toform such a film with thickness more than a sub-micron order. Further,the SOG is fragile and it is difficult to work the SOG.

Accordingly, a further object of the present invention is to provide apattern forming method in which it is possible to form a fine patternwith efficiency and with safety, by using the shorter wave less than 350nm.

A further object of the present invention is to provide a method offorming a conductive (SiC), a semi-conductive (a-Si), a insulating(SiO), or a light transmissive (SiO₂) thin film, materials for aninsulating film of which the film characteristics and the workabilityare improved by using the thin film forming method, a semiconductordevice in which the film materials are used, and a method thereof.

The above-mentioned problems are solved by using the followingmaterials, films, semiconductor devices and methods.

(1) A fluorine-containing silicon network polymer represented by thefollowing general formula, having molecular weight of 1,000 to 100,000.##STR1## (where, R is aromatic group or alkyl group containing at leastone fluorine, and n is integer.)

(2) A fluorine-containing silicon network polymer consisting of thereactant of tetrahalosilane of chemical formula 1 and organohalogenideof chemical formula 2.

    SiX.sub.4                                                  (1)

    RZ                                                         (2)

(where, R is aromatic group or alkyl group containing at least onefluorine, X is bromine, iodine, chlorine, Z is bromine, iodine,chlorine, and X and Z can be different materials to each other.)

(3) An insulating film comprised of the fluorine-containing siliconnetwork polymer.

The fluorine-containing silicon network polymer can be obtained byinserting a pair of electrodes one of which is a magnesium electrodeinto mixed solution of the tetrahalosilane of chemical formula 1 and theorganohalogenide of chemical formula 2, applying a voltage between thepair of electrodes to react, and coating the reacted solution on thesubstrate to form a thin film.

It should be appreciated that the thin film can be thermally treated at200° C. to 1,000° C., in the presence of oxygen.

Further, it should be appreciated that an electromagnetic wave can beirradiated on the thin film in the presence of oxygen.

Furthermore, it should be appreciated that an electromagnetic wave canbe irradiated on the thin film in the presence of oxygen, and then thethin film can be thermally treated at 200° C. to 1,000° C., in thepresence of oxygen.

It is possible directly to form the thin film on the electronic deviceby coating.

The fluorine-containing silicon network polymer which has never beenobtained in the prior art can be obtained by reacting thetetrahalosilane and the organohalogenide in the presence of themagnesium electrodes. The insulating film with low permittivity andhaving the improved characteristics can be provided by using the newpolymer.

The advantages of the above reaction are in that the range ofapplications of the reaction is very broad and the yield is very high.

Next, a synthetic method will be explained.

Firstly, organohalogenide reacted with fluorine is reacted withmagnesium to produce Grignard reagent. The produced Grignard reagent andtetrahalosilane are reacted with each other to producetrihaloorganosilane. Finally, the desired fluorosilicon network polymeris obtained by the condensation of the triholoorganosilane. Accordingly,instead of the above-mentioned fluoroorganohalogenide, it is possible touse any materials which can produce Grignard reagent, such asfluorohaloallyl, fluorohaloalkyl, etc.

Further, the yield of the produced polymer is higher than that due tothe Wurtz's reaction. An R content of the polymer can be adjusted bychanging the ratio of SiX₄ to RZ.

The synthesis of polysilane having fluoroalkyl group is disclosed inJapanese Patent Application Laid-Open No. 3-258834 (1991). However, itrelates to straight chain polysilane, and thus it is different from thepresent invention.

By using the method described in the Journal of The Japan Society ofApplied Physics, Volume 77, 2796 (1995), it is possible to make anoxidation film by the produced fluorosilicon network polymer and toperform the patterning. The relative permittivity of the oxidation filmobtained is lower than that due to the conventional silicon networkpolymer. It is, therefore, more advantageous to improve the performanceof electronic devices.

The film obtained by oxidizing the fluorosilicon network polymer issmall in film stress, and thus it is suitable to use as an insulatinglayer for semiconductors.

(4) A method of forming a thin film wherein after forming a thin film ofsilicon network polymer on a substrate at least one of the followingsteps are carried out: (a) irradiating an electromagnetic wave to thefilm of the silicon network polymer in the presence of oxygen, (b)thermally treating the film of silicon network polymer at 200° C. to1,000° C. in the presence of oxygen.

(5) A method of forming a thin film which comprises the steps of:forming a thin film of silicon network polymer on a substrate;irradiating an electromagnetic wave to the film of the silicon networkpolymer; thermally treating the film of silicon network polymer at 200°C. to 1,000° C.

(6) A method of forming a thin film wherein the silicon network polymeris made by the polymerization of organic metal compound represented bythe following formulas 3 and/or 4. ##STR2## (Where, R₁, R₂, R₃ arearomatic group, fluoroaliphatic group, or aliphatic group in which thecarbon number is equal to or less than 10, and they may be differentfrom one another or the same as others)

(7) A method of forming a thin film according to the above-mentionedparagraph (6), wherein the silicon network polymer is made by reactingand polymerizing organic metal compound represented by the followingformulas 3 and/or 4 with at least one of alloy of alkali metals, copperand magnesium. ##STR3## (Where, R₁, R₂, R₃ are aromatic group,fluoroaliphatic group, or aliphatic group in which the carbon number isequal to or less than 10, and they may be different from one another orthe same as others)

(8) An electrically insulating thin film made by irradiating anelectromagnetic wave to the film of the silicon network polymer in thepresence of oxygen, thermally treating the thin film of silicon networkpolymer at 200° C. to 1,000° C. in the presence of oxygen.

(9) A method of forming an electrically insulating thin film whichcomprises the steps of: forming a thin film of silicon network polymeron a substrate, irradiating an electromagnetic wave to the film of thesilicon network polymer in the presence of oxygen, and then thermallytreating the thin film of silicon network polymer at 200° C. to 1,000°C. in the presence of oxygen.

(10) A semiconductor device which uses the insulating layer as aninter-layer insulating film, made by forming a thin film of siliconnetwork polymer on a substrate, irradiating an electromagnetic wave tothe film of the silicon network polymer in the presence of oxygen, andthen thermally treating the thin film of silicon network polymer at 200°C. to 1000° C. in the presence of oxygen.

(11) A method of manufacturing a semiconductor device which uses aninsulating layer as an inter-layer insulating film, made by forming athin film of silicon network polymer on a substrate, irradiating anelectromagnetic wave to the thin film of the silicon network polymer inthe presence of oxygen, and then thermally treating the film of siliconnetwork polymer at 200° C. to 1,000° C. in the presence of oxygen.

(12) A semiconductor device which uses the insulating layer flatten by achemical machinery polishing method as an inter-layer insulating film,in which the insulating layer is made by forming a thin film of siliconnetwork polymer on a substrate, irradiating an electromagnetic wave tothe thin film of the silicon network polymer in the presence of oxygen,and then thermally treating the thin film of silicon network polymer at200° C. to 1,000° C. in the presence of oxygen.

(13) A method of manufacturing a semiconductor device which comprises astep of flattening the insulating layer by a chemical machinerypolishing method, prepared by irradiating an electromagnetic wave to thethin film of the silicon network polymer formed on a substrate in thepresence of oxygen, and then thermally treating the film of siliconnetwork polymer at 200° C. to 1,000° C. in the presence of oxygen.

(14) A semiconductor device which uses the insulating layer as aconductive layer and/or a semi-conductive layer, prepared by forming athin film of silicon network polymer on a substrate, irradiating anelectromagnetic wave to the film of the silicon network polymer in thepresence of oxygen, and then thermally treating the thin film of siliconnetwork polymer at 200° C. to 1000° C. in the presence of oxygen.

(15) A method of manufacturing a semiconductor device wherein theinsulating layer is used as a conductive layer and/or a semi-conductivelayer, made by forming a thin film of silicon network polymer on asubstrate, irradiating an electromagnetic wave to the film of thesilicon network polymer in the presence of oxygen, and then thermallytreating the thin film of silicon network polymer at 200° C. to 1,000°C. in the presence of oxygen.

The feature of the present invention is in that fine patterns are formedby performing the irradiation of an electromagnetic wave and the heattreatment using the material of which characteristics, for example, inthermal resistance is changed by the irradiation of the electromagneticwave, without performing the wet etching or the dry etching as carriedout in the prior art. It is, further, possible to form a useful thinfilm by using only heat treatment without irradiating theelectromagnetic wave. In case that network polysilane having fluoroalkylgroup is used, characteristics advantageous to improve thecharacteristics of a high speed electronic device, because thedielectric constant of the insulating film obtained becomes low. Whilethe synthesis of the polysilane having fluoroalkyl group is disclosed inJapanese Patent Application Laid-Open No. 3-258834, the disclosureconcerns straight chain polysilane, and thus it is impossible to formfine patterns like the present invention. In order to change the thermalresistance of a thin film by irradiating an electromagnetic wave, it isnecessary to use the silicon network polymer according to the presentinvention in which photooxidation reaction, photobridge reaction,photodecomposition reaction, etc., can be occurred.

The operation of the present invention will be explained hereinafter,taking as an example of the photooxidation-bridging reaction of siliconnetwork polymer.

Silicon network polymer resolved into organic solvent such as tolueneare painted and dried on the substrate on which patterns are formed byusing a spin coating or dipping method to form a thin film with eventhickness. Next, an electromagnetic wave with wavelengths of 150 nm to350 nm is irradiated onto the thin film of silicon network polymer inthe presence of oxygen. Si--Si bonding of the polysilane structure inthe thin film of silicon network polymer is cut out at an irradiatedarea, and bonds to oxygen to produce the structure containing many SiOskeletons. In this process, the silicon network polymer of the presentinvention takes oxygen into its molecular structure to expand in volume.

Then, the polymer is thermally treated at 200° C. to 1,000° C. in avacuum. The thin film of silicon network polymer at an unexposed area isdecomposed and volatilized from the substrate, or is thermallydecomposed to become a semi-conductive thin film such as SiC, amorphousSi, etc. Because the silicon network polymer is thermally stable at aheating temperature less than 200° C., it is not decomposed andconverted into SiO, amorphous Si, etc.

Because at the exposed area the SiO with high thermal resistance hasbeen already formed, the SiO area remains on the substrate even afterthe heat treatment. As a result, the negative pattern is formed. If thetemperature of the heat treatment for the substrate is more than 1,000°C., the SiO skeleton portion at the exposed area also is volatilized.Therefore, no film remains on the substrate.

The inventors applied the same exposing and heating process as above tostraight chain polysilane. As a result, there was no polysilane film onthe substrate at both the exposed area and the unexposed area, after theheat treatment. The reason lies in that the thermal resistance ofstraight chain polysilane is low.

The heat stability of the silicon network polymer of the presentinvention can be controlled by changing the formula ratio of the organicmetal compound represented by the formulas 1 and 2 in polymerizationreaction. As the formula ratio is increased, the heat stability becomeshigh. If it is necessary to form no fine pattern, it is possible toabbreviated the exposure process. Even if the silicon network polymerformed by abbreviating the exposure process is thermally treated at 200°C. to 1,000° C. in the presence of oxygen, an insulating film of whichthe characteristic of electricity is excellent. Further, by oxydizingsilicon network polymer without heating it, irradiating light to it inthe presence of oxygen, it is possible to obtain an insulating filmhaving an improved characteristic in electricity. If necessary, both thephotoreaction and the thermal reaction can be used or either of them canbe used. The volume expansion due to oxidation reaction can becontrolled according to the stage of the process of the photo-oxidationreaction and the thermal oxidation reaction and according to the stageof the process of the thermal decomposition reaction of the organicgroup. Finally, it is possible to eliminate the volume expansion of thethin film or occur the volumetric shrinkage.

In case that the formed thin film is applied to a semiconductor device,a mechanical characteristic of the thin film becomes very important. Ifthe film to be formed is shrunken in the process of forming, the tensilestress is generated. Therefore, the formed film is fragile and is apt tocrack due to a small external force. While, If the film to be formed isexpanded in the process of forming, the compression stress is generated.It is, therefore, hard to crack and extremely advantageous to work thefilm.

Because the film containing many SiO skeletons according to the presentinvention can control the volume expansion and the film stress generatedas described above, it is optimum to use in the manufacturing process ofa semiconductor device. It is desirable that in order to prevent a thinfilm from cracking, it needs to expand the film in the process offorming, or suppress the amount of shrinkage to the minimum amount.Because the thin film of silicon network polymer according to thepresent invention is excellent in a coating characteristic and a filmcharacteristic, the thickness of the film to be formed is not limited.If a thin film is formed by using spin coating, it is easiest to obtaina thin film with even thickness of 0.1 μm to 1.0 μm.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a GPC chart of poly (pentafluorophenylsilane) according to thepresent invention.

FIG. 2 is a view of Raman spectrum of poly (pentafluorophenylsilane)according to the present invention.

FIG. 3 is a view of visible ultraviolet absorption spectrum of poly(pentafluorophenylsilane) according to the present invention.

FIG. 4 is a sectional view of an aluminum double-layer-wiring substrateformed on a silicon wafer.

FIG. 5 is a view of infrared transmission spectra at the exposed areaand the unexposed area of a poly (phenylsilane) thin film, measuredafter heating.

FIG. 6 is a graph showing the current-voltage characteristic of ann-type silicon substrate/SiC thin film.

FIG. 7 is a view of far infrared transmission spectrum at the unexposedarea of a poly (n-propylsilane) thin film, measured after heating.

FIG. 8 is a graph showing the current-voltage characteristic of a p-njunction of p-doped amorphous silicon of which the precursor body is ann-type silicon and poly (n-propylsilane).

FIG. 9 is a sectional view of an aluminum double-layer-wiring substrateformed on a silicon substrate.

BEST MORD FOR CARRING OUT THE INVENTION

Embodiments of the present invention will be explained

(Embodiment 1)

Tetrahydrafuran solution, 200 ml, of 0.4 mol of tetrachrolosilane and0.4 mol of pentafluorobromobenzene was dropped into a nitrogen-convertedflask provided with a magnesium operation electrode and a pair of nickelelectrodes by using a dropping funnel, with ice-cooling. The Grignardreaction of tetrachrolosilane and pentafluorobromobenzene was performedunder the circulating flow of solvent.

Reaction was performed at 0° C. during 3 hours, with electric potentialscanning at 50 mV/sec between -3 V and 0 V applied between theelectrodes. The reacted solution is poured into methanol of 100 ml, andre-precipitated and refined by using distilled water of 500 ml. Theyield was 51.3%.

The average molecular weight of polystylene conversion measured by GPCwas 14,240.

FIG. 1 shows a GPC chart of the obtained poly (pentafluorophenylsilane),and FIG. 2 shows Raman spectrum of the polymer. It is understood thatthe spectrum of Si--Si bond is broad and networked. The ACS SymposiumSeries 579,408 (1994) discloses that the vibration spectrum of thenetworked polysilane becomes broad.

FIG. 3 shows a visible ultraviolet absorption spectrum of the obtainedpolymer. The absorption due to pentafluorophenyl group appears in theneighborhood of 270 nm. In FIG. 3, graph a shows 1 m mol/l THF solutionof poly (pentasilane), and graph b shows 1 m mol/l THF solution of poly(pentafluorophenylsilane).

Further, Table 1 shows the result of measurement of XPS (X-rayPhotoelectron Spectroscopy) the obtained polymer. Signals indicative offluorine, oxygen and carbon are observed. It is, therefore, understoodthat the desired network polymer is obtained. Where, it seems that theobserved oxygen atom is introduced by the reaction with methanol whenthe reaction is stopped.

                  TABLE 1                                                         ______________________________________                                        ATOM       (ORBIT)  RELATIVE INTENSITY                                        ______________________________________                                        F          (1s)     21.66                                                     Si         (2p)               6.20                                            C          (1S)              61.29                                            O          (1s)              10.85                                            ______________________________________                                    

(Embodiment 2)

Pentafluorobromobenzene is changed for nonafluoroiodobutane, and thesynthesis is carried out in the same way as Embodiment 1. As a result,poly (nonafluorobutylsilane) was obtained with the yield of 55%.

(Embodiment 3)

Pentafluorobromobenzene is changed for heptafluoroiodopropane, and thesynthesis is carried out in the same way as Embodiment 1. As a result,poly (heptafluoropropylsilane) was obtained with the yield of 50%.

(Embodiment 4)

Toluene solution of 20 wt % of the poly (pentafluorophenylsilane)obtained in Embodiment 1 was spin-coated on a silicon wafer. Afterexposing it for 10 minutes by using 500 W mercury lamp in the presenceof oxygen, the thermal treatment is carried out for 1 hour at 500° C. ina vacuum. As a result, an insulating thin film with thickness of 1.5 μmwas obtained.

We observed the insulating film by using a microscope and confirmed thatthere is no crack due to the shrinkage of a thin film in the process ofheating, and that the formed film is very fine and uniform. Thedielectric constant of the film was 2.7, measured by using frequency of1 kHz.

(Embodiment 5)

Toluene solution of 20 wt % of the poly (heptafluoropropylsilane)obtained in Embodiment 3 was spin-coated on a silicon wafer. Afterexposing it for 10 minutes by using 500 W mercury lamp in the presenceof oxygen, the thermal treatment was carried out for 1 hour at 400° C.in a vacuum. As a result, an insulating thin film with thickness of 1.5μm was obtained.

We observed the insulating film by using a microscope and confirmed thatthere is no crack due to the shrinkage of a thin film in the process ofheating, and that the formed film is very fine and uniform. Thedielectric constant of the film was 2.5, measured by using frequency of1 kHz.

(Embodiment 6)

Toluene solution of 30 wt % of the poly (pentafluorophenylsilane)obtained in Embodiment 1 was spin-coated on a silicon wafer on which analuminum pattern (L/S=1 μm and 1 μm high) is formed, to form a film withthickness of 2 μm. After thermally treating the film for 1 hour at 400°C. in an air, it was flattened in its surface by using a CMP (ChemicalMachinery Polishing) method.

There is no crack due to the polishing, and that the formed insulatingfilm is very strong. The withstand voltage was 700 V/μm, and thedielectric constant was 2.5.

FIG. 4 is a sectional view of an aluminum double-layer-wiring substrateobtained by repeating the above-mentioned process.

Aluminum wiring 2 and aluminum pier 3 are formed by normally etching thealuminum deposited by using a sputtering method. By forming theinsulating film 4 on the silicon wafer 1 on which active areas areformed, it is possible to obtain an integrated circuit with high speedresponse.

(Embodiment 7)

After dropping the solution produced by dissolving 40 m mol oftrichrolophenylsilane (phenyl group is used instead of R₁ in formula 3)to 5 ml of toluene, into the solution produced by adding 90 m mol ofmetallic sodium to 4o ml of toluene heated to 110° C. and agitating anddistributing it, the reaction is carried out for 1 hour. After coolingthe reacted solution, supernatant liquid obtained by eliminatinginsoluble matters using a centrifugal separator is dropped intoexcessive methanol, and re-precipitated and refined to obtain poly(phenylsilane). 20 wt % of toluene solution of poly (phenylsilane) wasspin-coated on a substrate. After exposing it through a mask pattern for10 minutes by using 500 W mercury lamp in the presence of oxygen, thethermal treatment was carried out for 1 hour at 700° C. in a vacuum. Asa result, a negative pattern with the minimum L/S (line and space)=0.75μm was formed (the thickness of the film is 1.5 μm) at both the exposedarea and the unexposed area. We observed the negative pattern by using amicroscope and confirmed that there is no crack due to the shrinkage ofa thin film in the process of heating, and that the formed film is veryfine and uniform.

FIG. 5 shows infrared transmission spectra at both the exposed area andthe unexposed area of the above-mentioned pattern. While at the exposedarea a signal of SiO in the neighborhood of 800 cm⁻¹ is remarkable, atthe unexposed area a signal of SiC in the neighborhood of 800 cm⁻¹ isremarkable

(Embodiment 8)

An electrode is formed by spin-coating the poly (phenyl silane) inEmbodiment 7 on an n-type silicon substrate, thermally treating forlhour at 700° C. in a vacuum without exposure to light to form an SiCthin film on an n-type silicon substrate, and evaporating gold onto theSiC portion. Further, an indium electrode is formed on an n-type siliconsubstrate. A bonding characteristic of the n-type silicon substrate/SiCthin film is measured from an electric current/voltage curve obtained atthe electrodes. The results of measurement is shown in FIG. 6. bythermal treatment of poly (phenylsilane), hetero-bonding of the n-typesilicon substrate and the SiC thin film having a rectifyingcharacteristic was formed easily.

(Embodiment 9)

20 wt % of toluene solution of poly (n-propylsilane) (n-propyl group isused instead of R₁ of formula 3) obtained in a way similar to that ofEmbodiment 7 was spin-coated on a substrate. After exposing it through amask pattern by using a KrF excimer laser in a vacuum, thermal treatmentwas carried out for 30 minutes at 350° C. in a vacuum. As a result, apositive pattern with the minimum L/S (line and space)=0.25 μm wasformed (the thickness of the film is 0.1 μm) at both the exposed areaand the unexposed area. It was seen that an amorphous silicon thin filmis formed at the unexposed area from the analysis of the far infraredspectrum shown in FIG. 3.

(Embodiment 10)

After dropping the solution produced by dissolving 8 m mol oftrichrolopropylsilane (n-propyl group is used instead of R₁ in formula3) and 32 m mol of dichrolopropylsilane (n-propyl groups were usedinstead of R₁, R₂ and R₃ in formula 3) to 5 ml of toluene, into thesolution produced by adding 90 m mol of metallic sodium to 4o ml oftoluene heated to 110° C. and agitating and distributing it, thereaction was carried out for 1 hour. After cooling the reacted solution,supernatant liquid obtained by eliminating insoluble matters using acentrifugal separator was dropped into excessive methanol, andreprecipitated and refined to obtain poly (n-propylsilane). 20 wt % oftoluene solution of poly (n-propylsilane) was spin-coated on asubstrate. After exposing it through a mask pattern by using the KrFexcimer laser in the presence of oxygen, the thermal treatment wascarried out for 1 hour at 500° C. in a vacuum.

As a result, a negative pattern of SiO₂ with the minimum L/S (line andspace)=0.25 gm was formed (the thickness of the film is 1.5 μm) at boththe exposed area and the unexposed area. We observed the negativepattern by using a microscope and confirmed that there is no crack dueto the shrinkage of a thin film in the process of heating, and that theformed film is very fine and uniform.

(Embodiment 11)

Toluene solution of 20 wt % of the same poly (n-propylsilane) as oneobtained in Embodiment 4 was spin-coated on an n-type silicon substrateto form a poly (n-propylsilane) thin film. By thermally treating thefilm for 30 minutes at 400° C. in a vacuum, it was converted into anamorphous silicon thin film. By doping phosphorus into the amorphoussilicon thin film as the impurity, p-type amorphous silicon thin filmwas formed. A p-n junction was formed by using the n-type silicon andp-type amorphous silicon thin film, and the characteristic of thejunction was measured. The result of measurement is shown in FIG. 8.

(Embodiment 12)

Toluene solution of 30 wt % of the same poly (phenylsilane) as one inEmbodiment 7 was spin-coated on a silicon substrate 1 on which analuminum wiring 2 of L/S=1 μm and 1 μm high is formed, to form a filmwith thickness of 2 μtm. After thermally treating the film for 1 hour at400° C. in an air, it was flattened in its surface by using a CMP(Chemical Machinery Polishing) method. There is no crack due to thepolishing, and that the formed insulating film 4 is very strong. Thewithstand voltage for insulation was 600 V/μm, and the dielectricconstant was 3.2.

FIG. 9 is a sectional view of an aluminum double-layer-wiring substrateobtained by repeating the above-mentioned process. Aluminum wiring 2 andaluminum pier 3 are formed by normally etching the aluminum deposited byusing a sputtering method. By forming the wiring on the siliconsubstrate on which active areas are formed, it is possible to obtain anintegrated circuit.

New fluorosilicon network polymer of the present invention is excellentin a coating characteristic and a film characteristic. It is, therefore,possible to provide an electronic device with high performance and withhigh speed response by using the polymer as an insulating film forelectronic devices.

By irradiating an electromagnetic wave and thermally treating aftercoating a thin film of polysilane, it is possible to form easily andarbitrarily the thin film having the functions of electricalconductivity (SiC), semi-conductivity (a-Si), insulation (SiO₂), lighttransmission (SiO₂), etc. It is, therefore, possible to perform easilythe fine work for a semiconductor, etc.

INDUSTRIAL APPLICABILITY

The present invention relates to silicon network polymer containingfluorine in polymer structure, an insulating film and a manufacturingmethod thereof.

The silicon network polymer containing fluorine in polymer structure isuseful for a method of forming a thin film by using a photolithographymethod, a semiconductor device using the thin film or a method ofmanufacturing the semiconductor device.

We claim:
 1. A fluorine-containing silicon network polymer representedby the following general formula: ##STR4## where, R is an aromatic groupor alkyl group containing at least one fluorine, and n is an integer,the polymer having a molecular weight of 1,000 to 100,000.
 2. afluorine-containing silicon network polymer consisting of the reactionproduct of tetrahalosilane of chemical formula 1 and organohalogenide ofchemical formula 2:

    SiX.sub.4                                                  ( 1)

    RZ                                                         (2)

where, R is an aromatic group or alkyl group containing at least onefluorine, X is selected from the group consisting of bromine, iodine andchlorine, Z is selected from the group consisting of bromine, iodine andchlorine, and X and Z can be different materials from each other.
 3. Aninsulating film comprised of fluorine-containing silicon network polymerrepresented by the following general formula: ##STR5## where, R is anaromatic group or alkyl group containing at least one fluorine, and n isan integer, said polymer having a molecular weight of 1,000 to 100,000.4. An insulating film comprised of fluorine-containing silicon networkpolymer consisting of the reaction product of tetrahalosilane ofchemical formula 1 and organohalogenide of chemical formula 2:

    SiX.sub.4                                                  ( 1)

    RZ                                                         (2)

where, R is an aromatic group or alkyl group containing at least onefluorine, X is selected from the group consisting of bromine, iodine andchlorine, Z is selected from the group consisting of bromine, iodine andchlorine, and X and Z an be different materials from each other.
 5. Aninsulating film comprised of fluorine-containing silicon network polymeraccording to claim 3 or 4, wherein said insulating film is one thatelectromagnetic waves are irradiated in the presence of oxygen.
 6. Amethod of manufacturing fluorine containing silicon network polymercomprising the steps of:inserting a pair of electrodes one of which is amagnesium electrode into mixed solution of tetrahalosilane of chemicalformula 1 and organohalogenide of chemical formula 2:

    SiX.sub.4                                                  ( 1)

    RZ                                                         (2)

where, R is an aromatic group or alkyl group containing at least onefluorine, X is selected from the group consisting of bromine, iodine andchlorine, Z is selected from the group consisting of bromine, iodine andchlorine, and X and Z can be different materials from each other,applying a voltage across said pair of electrodes to react thetetrahalosilane and the organohalogenide, so as to form a reactedsolution, and coating the reacted solution on a substrate to form a thinfilm.
 7. A method of manufacturing fluorine containing silicon networkpolymer according to claim 6, wherein the thin film is thermally treatedat 200° C. to 1,000° C. in the presence of oxygen.
 8. A method ofmanufacturing fluorine containing silicon network polymer according toclaim 6, wherein electromagnetic waves are irradiated on the thin filmin the presence of oxygen.
 9. A method of manufacturing fluorinecontaining silicon network polymer according to claim 6, whereinelectromagnetic waves are irradiated on the thin film in the presence ofoxygen, and then the thin film is thermally treated at 200° C. to 1,000°C. in the presence of oxygen.
 10. An electronic device, wherein aninsulating layer of a circuit substrate of said electronic device isconfigured with an insulating film comprised of fluorine-containingsilicon network polymer represented by the following general formula:##STR6## where, R is an aromatic group or alkyl group containing atleast one fluorine, and n is an integer, the polymer having a molecularweight of 1,000 to 100,000.
 11. A method of forming a thin film, whereinafter forming a thin film of silicon network polymer on a substrate atleast one of the following steps are carried out: (a) irradiatingelectromagnetic waves to the film of the silicon network polymer in thepresence of oxygen, and (b) thermally treating the film of siliconnetwork polymer at 200° C. to 1,000° C. in the presence of oxygen.
 12. Amethod of forming a thin film which comprises the steps of: forming athin film of silicon network polymer on a substrate; irradiatingelectromagnetic waves to the film of the silicon network polymer; andthermally treating the film of silicon network polymer at 200° C. to1000° C.
 13. A method of forming a thin film according to claim 11 or12, wherein the silicon network polymer is made by the polymerization oforganic metal compound represented by the following formulas 3 and/or 4,##STR7## Where, R₁, R₂, R₃, are aromatic group, fluoroaliphatic group,or aliphatic group in which the carbon number is equal to or less than10, and they may be different from one another or the same as eachother.
 14. A method of forming a thin film according to claim 13,wherein the silicon network polymer is made by reacting and polymerizing(1) organic metal compound represented by the following formulas 3and/or 4 ##STR8## where, R₁, R₂, R₃ are aromatic group, fluoroaliphaticgroup, or aliphatic group in which the carbon number is equal to or lessthan 10, and they may be different from one another or the same as eachother, with (2) at least one of alloy of alkali metals, copper ormagnesium.
 15. An electrically insulating thin film made by irradiatingelectromagnetic waves to the film of the silicon network polymer in thepresence of oxygen, and thermally treating the thin film of siliconnetwork polymer at 200° C. to 1000° C. in the presence of oxygen.
 16. Amethod of forming an electrically insulating thin film which comprisesthe steps of: forming a thin film of silicon network polymer on asubstrate, irradiating electromagnetic waves to the film of the siliconnetwork polymer in the presence of oxygen, and then thermally treatingthe thin film of silicon network polymer at 200° C. to 1,000° C. in thepresence of oxygen.
 17. A semiconductor device which uses an insulatinglayer as an inter-layer insulating film, made by forming a thin film ofsilicon network polymer on a substrate, irradiating electromagneticwaves to the film of the silicon network polymer in the presence ofoxygen, and then thermally treating the thin film of silicon networkpolymer at 200° C. to 1,000° C. in the presence of oxygen.
 18. A methodof manufacturing a semiconductor device which uses an insulating layeras an inter-layer insulating film, made by forming a thin film ofsilicon network polymer on a substrate, irradiating electromagneticwaves to the thin film of the silicon network polymer in the presence ofoxygen, and then thermally treating the film of silicon network polymerat 200° C. to 1,000° C. in the presence of oxygen.
 19. A semiconductordevice comprising an insulating layer flattened by a chemical machinerypolishing method as an inter-layer insulating film, in which theinsulating layer is made by forming a thin film of silicon networkpolymer on a substrate, irradiating electromagnetic waves to the thinfilm of the silicon network polymer in the presence of oxygen, and thenthermally treating the thin film of silicon network polymer at 200° C.to 1000° C. in the presence of oxygen.
 20. A method of manufacturing asemiconductor device which comprises a step of flattening an insulatinglayer by a chemical machinery polishing method, the insulating layerbeing made by irradiating electromagnetic waves to the thin film of thesilicon network polymer formed on a substrate in the presence of oxygen,and then thermally treating the film of silicon network polymer at 200°C. to 1,000° C. in the presence of oxygen.
 21. A semiconductor devicewhich uses the insulating layer as a conductive layer and/or asemi-conductive layer, made by forming a thin film of silicon networkpolymer on a substrate, irradiating electromagnetic waves to the film ofthe silicon network polymer in the presence of oxygen, and thenthermally treating the thin film of silicon network polymer at 200° C.to 1000° C. in the presence of oxygen.
 22. A method of manufacturing asemiconductor device wherein the insulating layer is used as aconductive layer and/or a semi-conductive layer, made by forming a thinfilm of silicon network polymer on a substrate, irradiatingelectromagnetic waves to the film of the silicon network polymer in thepresence of oxygen, and then thermally treating the thin film of siliconnetwork polymer at 200° C. to 1000° C. in the presence of oxygen.
 23. Afluorine-containing silicon network polymer according to claim 1 or 2,wherein said polymer is an amorphous fluorine-containing silicon networkpolymer.
 24. An insulating film according to claim 3 or 4, wherein saidpolymer is an amorphous fluorine-containing silicon network polymer. 25.An electronic device according to claim 10, wherein said polymer is anamorphous fluorine-containing silicon network polymer.
 26. A method offorming a thin film according to claim 11 or 12, wherein the siliconnetwork polymer is a fluorine-containing silicon network polymer.
 27. Amethod of forming a thin film according to claim 13, wherein the siliconnetwork polymer is a fluorine-containing silicon network polymer.
 28. Amethod of forming a thin film according to claim 14, wherein the siliconnetwork polymer is a fluorine-containing silicon network polymer.
 29. Anelectrically insulating thin film according to claim 15, wherein thesilicon network polymer is a fluorine-containing silicon networkpolymer.
 30. A method according to claim 16, wherein the silicon networkpolymer is a fluorine-containing silicon network polymer.
 31. Asemiconductor device according to claim 17, 19 or 21, wherein thesilicon network polymer is a fluorine-containing silicon networkpolymer.
 32. A method of manufacturing a semiconductor device accordingto claim 18, 20 or 22, wherein the silicon network polymer is afluorine-containing silicon network polymer.